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<pre><span class="sourceLineNo">001</span><a name="line.1"></a>
<span class="sourceLineNo">002</span>/*<a name="line.2"></a>
<span class="sourceLineNo">003</span> * Copyright (C) 2014 Archie L. Cobbs. All rights reserved.<a name="line.3"></a>
<span class="sourceLineNo">004</span> *<a name="line.4"></a>
<span class="sourceLineNo">005</span> * $Id: KVTransaction.html 939 2015-05-29 01:16:17Z archie.cobbs $<a name="line.5"></a>
<span class="sourceLineNo">006</span> */<a name="line.6"></a>
<span class="sourceLineNo">007</span><a name="line.7"></a>
<span class="sourceLineNo">008</span>package org.jsimpledb.kv;<a name="line.8"></a>
<span class="sourceLineNo">009</span><a name="line.9"></a>
<span class="sourceLineNo">010</span>/**<a name="line.10"></a>
<span class="sourceLineNo">011</span> * {@link KVDatabase} transaction API.<a name="line.11"></a>
<span class="sourceLineNo">012</span> *<a name="line.12"></a>
<span class="sourceLineNo">013</span> * &lt;p&gt;<a name="line.13"></a>
<span class="sourceLineNo">014</span> * Provides a transactional view into a {@link KVStore}.<a name="line.14"></a>
<span class="sourceLineNo">015</span> * &lt;/p&gt;<a name="line.15"></a>
<span class="sourceLineNo">016</span> *<a name="line.16"></a>
<span class="sourceLineNo">017</span> * &lt;p&gt;<a name="line.17"></a>
<span class="sourceLineNo">018</span> * Instances may throw {@link KVTransactionException} during any operation if the transaction cannot be continued.<a name="line.18"></a>
<span class="sourceLineNo">019</span> * In particular, {@link StaleTransactionException} is thrown by a transaction that is no longer open, and<a name="line.19"></a>
<span class="sourceLineNo">020</span> * {@link RetryTransactionException} is thrown when the transaction should be retried due to a transient<a name="line.20"></a>
<span class="sourceLineNo">021</span> * problem (such as a write conflict with another transaction). When {@link RetryTransactionException} is thrown by<a name="line.21"></a>
<span class="sourceLineNo">022</span> * {@link #commit}, the transaction may have actually been committed. Therefore, transactions should be written to be idempotent.<a name="line.22"></a>
<span class="sourceLineNo">023</span> * When any {@link KVTransactionException} is thrown, the transaction must still support invoking {@link #rollback},<a name="line.23"></a>
<span class="sourceLineNo">024</span> * but all other operations may throw {@link StaleTransactionException}.<a name="line.24"></a>
<span class="sourceLineNo">025</span> * &lt;/p&gt;<a name="line.25"></a>
<span class="sourceLineNo">026</span> *<a name="line.26"></a>
<span class="sourceLineNo">027</span> * &lt;p&gt;<a name="line.27"></a>
<span class="sourceLineNo">028</span> * If an instance throws a {@link KVTransactionException}, the transaction should be implicitly rolled back.<a name="line.28"></a>
<span class="sourceLineNo">029</span> * &lt;/p&gt;<a name="line.29"></a>
<span class="sourceLineNo">030</span> *<a name="line.30"></a>
<span class="sourceLineNo">031</span> * &lt;p&gt;<a name="line.31"></a>
<span class="sourceLineNo">032</span> * Implementations must throw {@link StaleTransactionException} if {@link #commit} or {@link #rollback} has already<a name="line.32"></a>
<span class="sourceLineNo">033</span> * been invoked, or if the {@link KVTransaction} instance is no longer usable for some other reason. In particular,<a name="line.33"></a>
<span class="sourceLineNo">034</span> * implementations should throw {@link TransactionTimeoutException} if an operation is attempted on a transaction<a name="line.34"></a>
<span class="sourceLineNo">035</span> * that has been held open past some maximum allowed time limit.<a name="line.35"></a>
<span class="sourceLineNo">036</span> * &lt;/p&gt;<a name="line.36"></a>
<span class="sourceLineNo">037</span> *<a name="line.37"></a>
<span class="sourceLineNo">038</span> * &lt;p&gt;<a name="line.38"></a>
<span class="sourceLineNo">039</span> * Implementations are responsible for ensuring modifications to {@code byte[]} arrays after method<a name="line.39"></a>
<span class="sourceLineNo">040</span> * invocations do no harm. This usually means {@code byte[]} array parameters and return values must be copied.<a name="line.40"></a>
<span class="sourceLineNo">041</span> * &lt;/p&gt;<a name="line.41"></a>
<span class="sourceLineNo">042</span> *<a name="line.42"></a>
<span class="sourceLineNo">043</span> * &lt;p&gt;<a name="line.43"></a>
<span class="sourceLineNo">044</span> * Accessing keys that start with {@code 0xff} is not supported and will result in {@link IllegalArgumentException}.<a name="line.44"></a>
<span class="sourceLineNo">045</span> * &lt;/p&gt;<a name="line.45"></a>
<span class="sourceLineNo">046</span> */<a name="line.46"></a>
<span class="sourceLineNo">047</span>public interface KVTransaction extends KVStore {<a name="line.47"></a>
<span class="sourceLineNo">048</span><a name="line.48"></a>
<span class="sourceLineNo">049</span>    /**<a name="line.49"></a>
<span class="sourceLineNo">050</span>     * Get the {@link KVDatabase} with which this instance is associated.<a name="line.50"></a>
<span class="sourceLineNo">051</span>     *<a name="line.51"></a>
<span class="sourceLineNo">052</span>     * @return associated database<a name="line.52"></a>
<span class="sourceLineNo">053</span>     */<a name="line.53"></a>
<span class="sourceLineNo">054</span>    KVDatabase getKVDatabase();<a name="line.54"></a>
<span class="sourceLineNo">055</span><a name="line.55"></a>
<span class="sourceLineNo">056</span>    /**<a name="line.56"></a>
<span class="sourceLineNo">057</span>     * Change the timeout for this transaction from its default value (optional operation).<a name="line.57"></a>
<span class="sourceLineNo">058</span>     *<a name="line.58"></a>
<span class="sourceLineNo">059</span>     * @param timeout transaction timeout in milliseconds, or zero for unlimited<a name="line.59"></a>
<span class="sourceLineNo">060</span>     * @throws UnsupportedOperationException if this transaction does not support timeouts<a name="line.60"></a>
<span class="sourceLineNo">061</span>     * @throws IllegalArgumentException if {@code timeout} is negative<a name="line.61"></a>
<span class="sourceLineNo">062</span>     * @throws StaleTransactionException if this transaction is no longer usable<a name="line.62"></a>
<span class="sourceLineNo">063</span>     */<a name="line.63"></a>
<span class="sourceLineNo">064</span>    void setTimeout(long timeout);<a name="line.64"></a>
<span class="sourceLineNo">065</span><a name="line.65"></a>
<span class="sourceLineNo">066</span>    /**<a name="line.66"></a>
<span class="sourceLineNo">067</span>     * Commit this transaction.<a name="line.67"></a>
<span class="sourceLineNo">068</span>     *<a name="line.68"></a>
<span class="sourceLineNo">069</span>     * &lt;p&gt;<a name="line.69"></a>
<span class="sourceLineNo">070</span>     * Note that if this method throws a {@link RetryTransactionException},<a name="line.70"></a>
<span class="sourceLineNo">071</span>     * the transaction was either successfully committed or rolled back. In either case,<a name="line.71"></a>
<span class="sourceLineNo">072</span>     * this instance is no longer usable.<a name="line.72"></a>
<span class="sourceLineNo">073</span>     * &lt;/p&gt;<a name="line.73"></a>
<span class="sourceLineNo">074</span>     *<a name="line.74"></a>
<span class="sourceLineNo">075</span>     * @throws StaleTransactionException if this transaction is no longer usable<a name="line.75"></a>
<span class="sourceLineNo">076</span>     * @throws RetryTransactionException if this transaction must be retried and is no longer usable<a name="line.76"></a>
<span class="sourceLineNo">077</span>     */<a name="line.77"></a>
<span class="sourceLineNo">078</span>    void commit();<a name="line.78"></a>
<span class="sourceLineNo">079</span><a name="line.79"></a>
<span class="sourceLineNo">080</span>    /**<a name="line.80"></a>
<span class="sourceLineNo">081</span>     * Cancel this transaction.<a name="line.81"></a>
<span class="sourceLineNo">082</span>     *<a name="line.82"></a>
<span class="sourceLineNo">083</span>     * &lt;p&gt;<a name="line.83"></a>
<span class="sourceLineNo">084</span>     * After this method returns, this instance is no longer usable.<a name="line.84"></a>
<span class="sourceLineNo">085</span>     *<a name="line.85"></a>
<span class="sourceLineNo">086</span>     * &lt;p&gt;<a name="line.86"></a>
<span class="sourceLineNo">087</span>     * This method may be invoked at any time, even after a previous invocation of<a name="line.87"></a>
<span class="sourceLineNo">088</span>     * {@link #commit} or {@link #rollback}, in which case the invocation will be ignored.<a name="line.88"></a>
<span class="sourceLineNo">089</span>     */<a name="line.89"></a>
<span class="sourceLineNo">090</span>    void rollback();<a name="line.90"></a>
<span class="sourceLineNo">091</span>}<a name="line.91"></a>
<span class="sourceLineNo">092</span><a name="line.92"></a>




























































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